1. Field of the Invention
This invention is generally concerned with the art of road and highway marking with strip or tape material, namely for providing a road or highway with centre-lines or with traffic lane-dividing lines or the like, prevailingly but not exclusively arranged lengthwise of the road.
More particularly, the present invention is concerned with the art of providing traffic signs of the above type, consisting of prefabricated tape material laid on the road surface upon a relatively thin underlayer generally comprising bitumen or asphalt or the like capable of thoroughly filling any road surface porosity, holes and hollows thus providing a tape material receiving, impervious, flat and planar surface which achieves a firm and permanent bond of the tape material to the road pavement.
Such underlayer is generally and usually indicated, in the art of road surface marking as above, by the word "primer layer" and therefore said expression will be made use of as this description proceeds and in the appended claims. This invention is principally concerned with the art of compounding, forming, applying on the road pavement and taking advantage of a new and advantageous primer layer as hereinbelow set forth.
2. Description of the Prior Art
The art of road surface marking with tape material is well worked one and a wide technical and patent literature thereabout exists. With relation to this art reference is herein made to the U.S. Pat. Nos. 3,399,607 and 3,587,415, of the present Applicant. As far as the machines and devices for providing a road pavement with such markings are concerned, reference is also made to the U.S. Pat. Nos. 3,007,838, 3,155,564, 3,235,436, 3,262,375 and 3,844,669, of the same Applicant.
It is also known that in relatively recent years the road marking tape materials have been substantially improved by making them "non skidding", that is adapted to provide a sure frictional adherence with the vehicles' tires, such a tape material being described, for example, in the applicant's U.S. Pat. No. 3,782,842. This provision, which is essential for traffic safety, has made it imperative that the tape material be most firmly secured to the road pavement to prevent detachment and stripping of the tape from said pavement, under the extremely severe inertial force exerted by fast and heavy vehicles such as in the event of emergency braking, accelerations and so on.
It is further known to those skilled in the art that the entire cycle of operations required for marking a road surface involves a considerable overall time. Such time will seriously disturb the availability of the highway, and the traffic must be kept far from the areas to be marked. The time involved in the process of complete setting of the primer layer, from the very time at which the primer layer composition is laid in contact with the road pavement to the very time at which the same composition has been hardened to form a consistent and load and stress resistant layer, is principally responsible for the evidently undesirable traffic disturbance.
It is therefore the principal object of the invention to provide a new and advantageous method for road surface marking, comprising the essential steps of forming a primer layer on said pavement and laying a prefabricated mark-forming tape material, the invention including a solution to the sharply antithetical problems of (i) shortening as much as possible such overall time and therefore decreasing the traffic disturbance and (ii) providing the most firm and permanent binding of the tape material to the road pavement by means of a completely set and properly hardened primer layer which is intimately secured to said pavement.